A cell structure of such fuel cells is disclosed in Patent Document 1, where the product is referred to as a “fuel cell”. The fuel cell described in Patent Document 1 includes a membrane electrode assembly in which an electrolyte membrane is sandwiched between an anode catalyst layer and a cathode catalyst layer, a plurality of gas-permeable films arranged such that each side of the membrane electrode assembly has a plurality of the films, a sealing gasket that is formed on the outer rims of the membrane electrode assembly and the gas-permeable layers on both sides by injection molding, and a separator that supports the multilayer structure.
In the above-described fuel cell, the gas-permeable layers include a gas diffusion layer made of a carbon cloth or a carbon paper. For the sake of impregnating the gas diffusion layer with resin, the sealing gasket is formed by injection molding. The sealing gasket serves not only as a sealer but also as a frame for supporting the membrane electrode assembly. In the above-described fuel cell, the outer rims of the gas-permeable layers on one side, the membrane electrode assembly and the gas permeable layers on the other side are sequentially displaced outward. This feature is intended to facilitate the impregnation with resin in the injection molding and to regulate a flow of gas that does not involved in the reaction so as to improve the power generation efficiency.